Battery emulator and methods of use

ABSTRACT

A dynamic battery emulator for replacing and mimicking the characteristics of a battery in a portable electronic device when the device is located in or on a vehicle can include a power control module capable of varying its output voltage to adapt to the voltage requirements of an attached portable electronic device; an input for conveying electrical power from the vehicle&#39;s electrical system to the power control module; an output for providing electrical power to the portable electronic device; an output for communicating a control signal from the power adaptor to the portable electronic device to selectively turn on and off the portable electronic device; a battery replacement module configured to replace the battery in a portable electronic device and including battery replacement circuitry for transferring electrical power from the power control module to the portable electronic device via the output for providing electrical power; an ignition sense controller for determining the power state of the vehicle&#39;s electrical system; and in communication with the ignition sense controller, at least one timer and switch for reducing the conveyance of electrical power from the vehicle&#39;s electrical system to the portable electronic device at a predetermined time after the vehicle&#39;s ignition or electrical system is turned off.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the priority of U.S. provisional patentapplication Ser. No. 61/264,975, entitled “Supplying External Power andControlling a Communication Device” and filed on Nov. 30, 2009.

FIELD OF THE INVENTION

The present invention relates to the field of electronics andcommunications. More particularly, the invention relates to batteryemulators for use with accessory electronic devices in cars, trucks, andother mobile vehicles.

BACKGROUND

Portable, battery-operated, electronic devices such as cell phones,media players, and location tracking devices are ubiquitous in today'sworld. To power or recharge these devices in a vehicle, power adaptorsthat connect a vehicle's electrical system directly to a portable devicecan be used. When the vehicle is operating or active, the electricalload on the vehicle from the power adapter and electronic device issmall compared to the overall electrical demands from the vehicleitself. When the vehicle is not operating or inactive, however, and thepower adapter and electronic device are left on, there will be acontinual and significant drain on the vehicle's battery. To preventdepletion of a vehicle's battery, power adaptors have been designed tosense when a vehicle's ignition is turned to the off position, and theneither turn off the device or drastically reduce its power consumption.

SUMMARY

The present invention was made during the development of a low-costsystem for tracking a fleet of vehicles using off-the-shelf portable,battery-operated, electronic devices such as global positioning system(GPS)-enabled location tracking devices or cell phones. Conventionalpower adaptors are not suited for this purpose for several reasons.First, conventional batteries used in conjunction with charger adapterswear out over years of use and can lose capacity in the harsh conditionsassociated with installation in a vehicle (e.g., extreme cold or heat,vibration, etc.). Second, after a vehicle's ignition is turned off,conventional batteries used in conjunction with charger adapters do notallow data acquisition and transmission by the device to be completedbefore the device is turned completely off to prevent the vehicle'sbattery from being drained. Third, conventional batteries used inconjunction with charger adapters are not able to be used with portableelectronic devices in different vehicles because of the large variationsin the ignition state and power supplied by different vehicles (whichmay range from 6-40V), as well as the inherent noise, spikes, and surgesassociated with each vehicle's electrical systems. For example,electrical systems utilized in different vehicles can range from 6 toover 40V and are prone to electrical noise. Fourth, conventionalbatteries used in conjunction with charger adapters do not provide thevery clean type of electrical power required for using vehicle-installedportable devices for tracking or monitoring in the real-world setting.For example, where a transceiver of a vehicle-mounted electronic devicecommunicates to a cell tower or other apparatus, the device draws alarge current and needs to be low output impedance for the transmission;but then needs to immediately shut the transmitter off and turn thereceiver on to receive a signal. Without a very clean power supply toprevent any noise from interfering with the received data, this wouldnot be possible.

To overcome these issues, the inventors used a great deal of ingenuityand effort to develop a battery emulator that replaces and mimics thecharacteristics of a portable electronic communication device's battery(e.g., impedance, voltage, current, and capacitance). In one embodiment,the battery emulator uses an analog to digital converter compatible withany vehicle having an electrical system (e.g., airplane, boat,motorcycle, electric car, golf cart, industrial equipment, forklifts,etc.) and a timer that allows a coupled portable electronic device tocomplete acquisition and logging (local storage or transmission to adistant server) of data before signaling the device to power down.Unlike a conventional power adaptor, a battery emulator of the inventioncan allow deterministic power levels (the voltage output can be changeddepending on signaling and an internal algorithm), full “ON”/“OFF”control to prevent excessive power drain from a vehicle's power system,filtering to remove noise out of the supplied power, fast (e.g., lessthan 1000, 900, 800, 700, 600, 500, 400, 200, or 100 nanoseconds)response to transient loads, surges, and spikes from a vehicle's powersystem and portable device load conditions. Importantly, regardless ofthe vehicle it is used with, it also can supply the propercharacteristics to emulate the replaced battery's impedance, current,and voltage so that the portable device operates as if a real batterywere attached to it (e.g., optimal performance for GPS-enabled devices,cell phones, and other noise and power sensitive electronic portabledevices, especially those with wireless data transceivers—which aresensitive to power supply noise). Thus in one embodiment, the batteryemulator of the invention can operate in conjunction with a vehicularelectrical system operating between 6V-30V (in a very noisy environment)to regulate the electrical power down to a low-impedance (e.g., lessthan 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, or 0.05 ohms) lowvoltage (e.g., about or less than 6, 5, 4, 3, or 2 V; about 3.7 or 5.7V; or between 1.5-38V) to emulate a real lithium ion or similar batteryusing a switching regulator optimized for low-noise, low outputimpedance, and additional filtering components to filter out theinherent switching frequency noise.

A battery emulator of the invention can employ circuitry to protect fromenergy spikes that can occur from the vehicle's power system (e.g., thereverse electro-motive force from an alternator, generators in anelectric vehicle, regenerative braking or similar systems). The batteryemulator can also include a power adapter and signaling circuitry thatlimits the power delivered to a device to prevent overloading itscharger and power system, provides the proper power up signaling as thereplaced battery, and prevents over-driving the signaling that coulddamage the internal circuitry of the device. It might also includecircuitry that can prevent dangerous short-circuit conditions andexcessive heat in the event of a failure while sourcing power to aportable electronic device, and allow the battery emulator to resumeproper operation once the failed condition is removed.

Accordingly, in one aspect, the invention features a dynamic batteryemulator for replacing and mimicking the characteristics of a battery ina portable electronic device when the device is located in or on avehicle. The dynamic battery emulator can include a power control modulecapable of varying its output voltage to adapt to the voltagerequirements of an attached portable electronic device; an input forconveying electrical power from the vehicle's electrical system to thepower control module; an output for providing electrical power to theportable electronic device; an output for communicating a control signalfrom the power adaptor to the portable electronic device to selectivelyturn on and off the portable electronic device; a battery replacementmodule configured to replace the battery in a portable electronic deviceand including battery replacement circuitry for transferring electricalpower from the power control module to the portable electronic devicevia the output for providing electrical power; an ignition sensecontroller for determining the power state of the vehicle's electricalsystem; and in communication with the ignition sense controller, atleast one timer and switch for reducing the conveyance of electricalpower from the vehicle's electrical system to the portable electronicdevice at a predetermined time after the vehicle's ignition orelectrical system is turned off. When connected to the portableelectronic device and the vehicle's electrical system, the batteryemulator can provide electrical power to the portable electronic deviceof same or about the same (e.g., +/−no more than 10, 9, 8, 7, 6, 5, 4,3, 2, or 1%) voltage, impedance, current, and capacitance as theportable electronic device's battery, and the delivered voltage andimpedance varies less than 3, 2, 1, or 0.5% during normal operation ofthe battery emulator.

The battery replacement module can convey power from the power controlmodule to terminals within the portable electronic device that areconfigured to receive electrical power from the portable electronicdevice's battery. The ignition sense controller can include an analog todigital converter for determining the power state of the vehicle'selectrical system. In cases where the vehicle's electrical power systemincludes an ignition system, the dynamic battery emulator can includediscrete circuitry which limits transmission of voltage spikes from theignition system. The dynamic battery emulator can be configured tooperate with a portable electronic device that includes a locationdetection system. The timer's predetermined time can be set to allow theportable electronic device to complete its pending data transferoperations before reducing the conveyance of electrical power from thevehicle's electrical system to the portable electronic device. Thedynamic battery emulator can also include and be controllable by amicroprocessor which can be controlled by a stimulus or an algorithm. Ina preferred designed, the battery emulator draws very little current(e.g., less than 10, 5, 4, 3, 2, 1 mA, and preferably less than 0.5 mA)from an external electrical system (e.g., a mobile vehicle's battery)when the vehicle is not operating.

In another aspect, the invention features a vehicle that includes adynamic battery emulator connected to the vehicle's electrical system.

In addition, the invention features a method including the steps of:connecting a battery emulator to a vehicle's electrical system; removinga battery from a battery slot of a portable electronic device; andinstalling the battery emulator into the battery slot of a portableelectronic device.

The invention also includes systems that use a battery emulator.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described below. All publications, patent applications,patents, and other references mentioned herein are incorporated byreference in their entirety. In the case of conflict, the presentspecification, including definitions will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting. Other features and advantages of the invention will beapparent from the following detailed description, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an electronic system that is useful for understanding thepresent invention.

FIG. 2 depicts a dynamic battery emulator, which is useful forunderstanding the present invention.

FIG. 3 depicts a power regulator, which is useful for understanding thepresent invention.

FIG. 4 depicts a block diagram of the dynamic battery emulator, which isuseful for understanding the present invention.

FIG. 5 depicts a schematic diagram of a power unit of the dynamicbattery emulator, which is useful for understanding the presentinvention.

FIG. 6 depicts a schematic diagram of a control circuit of the dynamicbattery emulator, which is useful for understanding the presentinvention.

FIG. 7 depicts a connector that connects the dynamic battery emulator toan electronic device, which is useful for understanding the presentinvention.

FIG. 8 depicts a connector that connects the dynamic battery emulator toan electronic device, which is useful for understanding the presentinvention.

FIG. 9 depicts a connector that connects the dynamic battery emulator toan electronic device, which is useful for understanding the presentinvention.

FIG. 10 is a flowchart that is useful for understanding the presentinvention.

DETAILED DESCRIPTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention, which can be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure. Further, the terms and phrases usedherein are not intended to be limiting but rather to provide anunderstandable description of the invention.

FIG. 1 depicts an electronic system 100 which includes a dynamic batteryemulator 110 which may be connected to a vehicle electrical system 120to receive power 130 and supply removable power 140 to operate anelectronic device 150. In addition, the battery emulator 110 also maycommunicate on_off signals 160 to the electronic device 150 toselectively turn on and turn off the electronic device when appropriate.The battery emulator 110 can also monitor the state of the vehicle'signition, for instance, by monitoring a vehicle on_off signal 170, aswell as a power cycle state of the electronic device 150, and processsuch information in order to determine when to supply power to theelectronic device 150. Further, the battery emulator 110 canautomatically initiate power-on and power-off sequences in theelectronic device 150 based on various conditions or states beingmonitored. The battery emulator 110 can emulate and replace the batteryin the electronic device 150, as well as prevent the electronic device150 from overly depleting a vehicle's battery. The battery emulator 110also can eliminate the need for user interaction to turn on and turn offthe electronic device 150 at appropriate times.

Based on the ignition state of the vehicle and the power on/off currentstate of the electronic device 150, the dynamic battery emulator 110 candetermine whether the last powering off of the electronic device 150 wasdue to a change in the vehicle's state. Accordingly, if the vehicle'spower on/off state has been determined to be in a powered on state,using an algorithm, a microcontroller can initiate signaling to power onthe electronic device. If the vehicle is in a powered off state, usingthe algorithm, the microcontroller sets a timer and continues to monitorthe vehicle's power state. If the vehicle's state does not change at theexpiration of this timer (which can be set for any amount of time, e.g.,about or no more than 10, 20, 30, 45, 60, 120, 240, 480, 1000, 2000,5000, or 10,000 seconds; 6, 12, 18, or 24 hours; or 2, 3, 4, or 5 days)the electronic device is shut off (although the microcontrollercontinues to monitor the vehicle state for any change in a very lowpower mode). If a change of state is detected and the timer has notexpired (the vehicle's power state was determined to be on), the timeris reset, and the electronic device is left in the powered on state.Again, using the algorithm, the microcontroller continues to monitor thevehicle for a change in power state.

In addition to the aforementioned algorithm, inputs from the electronicdevice to the microcontroller and associated circuitry (in the dynamicbattery emulator) determine whether the electronic device is in thepowered state. If the electronic device is determined to be in the onstate, then the signaling to power up the electronic device is not sentor initiated. This signaling could be as simple as activating a switchor as complex as specific waveforms or signaling to the electronicdevice. For example, a cellular phone might require a specific timedwaveform or signaling to power the device from the dynamic batteryemulator. If the vehicle's power on/off state has transitioned from apreviously on state to the off state, a programmable timer is set andthe algorithm is used to continue monitoring for a change in vehiclepower on/off state. Upon expiration of the timer with no change invehicle state, the signaling will be sent to turn off the electronicdevice and turn off the battery emulator circuitry to save current drainfrom the vehicle's battery or similar power supply. Again, themicrocontroller continually monitors the state of the vehicle for achange in state relative to its current state. During this vehicle's offstate, the dynamic battery emulator is placed in a low-current mode tominimize current drain on the vehicle's battery or similar power source.In one embodiment, the electronic device 150 can be a wirelesscommunication device. Examples of such wireless communication devicesinclude, but are not limited to, a mobile telephone (e.g., a cellulartelephone, a wide area network telephone, or the like), a mobile radio,a personal digital assistant, a mobile computer, a mobile terminal, anapplication specific device, a pager, or any other mobile device thatcan transmit and/or receive wireless communication signals. Theelectronic device 150 also can be or include a hands-free adapter, aglobal or similar positioning system, or any other electronic devicethat may be used within a vehicle. The electronic device 150 also can beany other type of electronic device that requires electrical power froma vehicle and the invention is not limited to these examples. Thebattery emulator 110 can be installed into a vehicle along with anembedded GPS enabled electronic device 150, and configured toautomatically turn on the electronic device 150 when the vehicle isstarted. The battery emulator 110 can maintain the electronic device 150in the on state for a desired period, using a timer, after the vehicleis turned off. Accordingly, the present invention allows for arelatively inexpensive electronic communications device 150 which haslocation services, GPS tracking or similar functionality. Thus, thepresent invention can provide an inexpensive option that allowscompanies and other organizations to monitor the present and pastlocations of their vehicles in real time without draining the vehicle'spower source.

FIG. 2 depicts a battery emulator 110 that includes a power controlmodule 210, an input 220 for receiving power from the vehicle, an output230 for providing power to the electronic device (to emulate its batteryor electrical power source), and an output 240 for communicating acontrol or data signal to the electronic device to selectively turn onand turn off the electronic device. The electrical power source is notlimited to batteries, but could be an alternate source of electricityused to power the electronic device.

The input 220 can feature one or more conductors, input terminals, orthe like. In one arrangement, the output 230 features a batteryreplacement and emulator module 232. The battery replacement andemulator module 232 can be configured to replace a battery in theelectronic device. Specifically, the battery replacement and emulatormodule 232 can receive power from the power control module 210 via oneor more conductors 234, and provide battery emulated power to terminalswithin the electronic device that are normally configured to receivepower from a battery. The circuits in the module are designed to emulatethe electrical properties of an actual battery that powers thesedevices. This power source can be modified to the specified voltage andpower rating of the electronic device. Unless a separate groundconnection is provided for the electronic device, in which case only asingle conductor 234 may be required, at least two conductors 234 may beprovided.

The battery replacement module 232 can be configured with any suitabledimensions and/or features as may be desired for operation in aparticular electronic device. In one arrangement, various types ofbattery replacement modules 232 can be provided, and an installer canselect the battery replacement module 232 best suited for installationinto the electronic device that is being used by its power requirements.

The output 240 can include a connector suitable for interfacing with theelectronic device. For example, the output 240 can include a universalserial bus (USB) connector or the mechanical outline of a cellular phonebattery with appropriate electrical contacts 242. Referring to FIG. 3,in another arrangement the output 240 of the battery emulator 110 caninclude a consumer electronics (CE) type connector 342. Still, any otherdesired connectors can be used and the invention is not limited in thisregard. This connector is used to provide signaling to and from thebattery emulator and the electronic device, but is not limited to otherconnections to provide the vehicle's state or other desired inputs.

FIG. 4 depicts a block diagram of a dynamic battery emulator 110 whichincludes a control circuit 410 that, based on a vehicle trigger voltagelevel 430, determines the power state of the vehicle's power on/offstate and uses circuitry and/or a software algorithm to determine andcontrol the power state of the electronic device and its associatedpower source 150. The control circuit 410 can include: analog inputs 412for measuring the trigger voltage (or similar signaling) to indicate thepower state of the vehicle; a controller 414 to make decisions based oninput signaling from vehicle and logic algorithm (circuitry andsoftware); a control/signaling circuit 416 to support the controller andto provide appropriate signaling to the electronic device connected toturn the device ON or OFF as defined in the algorithm (determined bydecisions from a vehicle's trigger voltage, the current power state ofthe device, and a timer); a programmable timer 418; and a controllerpower supply 420.

The control circuit 410 also can include an ignition sense controllerand an ignition sensor or similar device to determine the power state ofthe vehicle. The ignition sense controller can be embodied within thecontroller 414, and can send commands to the other portions of thedynamic battery emulator 110 and maintain various status flags.

The dynamic battery emulator 110 also can include a power unit 440,which can include an over-voltage protector 442 and a power supply 444.The design allows for operation in different vehicles with differentvoltage and power systems and has circuitry to prevent power spikes frominterfering with proper operation. The power supply is designed toprovide the correct power and is optimized to emulate a battery'selectrical characteristics such as but not limited to providing a lowimpedance and high capacitance to the electronic device.

The control unit/circuit 410 senses whether the vehicle's ignition is onor off, and uses power control logic, complex waveforms, or appropriatesignaling to control the power state of the electronic device 150 whenthe vehicle's ignition is turned back on. The control circuit 410 alsocan turn on and off the power supply 444 of the power unit 440. Based onthe ignition sense information, the control unit 410 automatically turnsthe electronic device 150 back on if the electronic device 150 has beendetermined to currently be in the off state. If, instead, the electronicdevice is determined to be in the off state 150 the control unit 410sends the control logic, complex waveform, or appropriate signaling toturn the electronic device 150 powered on. In this manner, the vehicle'sstate is used to control the electronic device and its emulated power soas to not unduly drain the vehicle's battery in the vehicle's off state.

Separately, or in combination with the above, the correctness of theignition sense line installation may be checked by first setting astatus flag to a default indication that the ignition sense line is notconnected. Thereafter, when a signal is detected on the ignition senseline (such as an indication that the ignition is being turned on), thestatus flag is changed to indicate a proper installation of the ignitionsense line and an indicator is set on the dynamic battery emulator. Thisindicator could be an LED, sound or vibrator at a set duration, etc. Ifa changed signal is detected on the ignition sense line, such as anindication that the ignition is being turned off, the timer is enabled.When the timer expires, and there has not been any ignition statechange, the indicator is unset on the dynamic battery emulator.

A dynamic battery emulator 110 employing the present invention utilizesa multi-state power management scheme to control its power and thepowered state of an attached electronic device 150. The power managementscheme looks to the state of the vehicle, the timer value, and thecurrent powered state of the electronic device 150 to determine whatactions should be taken. Thus, the power management method is dependentupon both the ignition state of the vehicle, the timer state, and thecurrent powered state of the associated electronic device 150.

A cellular telephone will be used as an illustrative example of theelectronic device 150; however, the present invention is not so limitedand, as noted, can function with any electronic device that receivespower from a vehicle. Further, a hands-free adapter with an incorporatedbattery charger will be used as an illustrative example of thecommunications accessory, but it is to be understood that the presentinvention is suitable for a wide variety of communications accessories,including hands-free adapters, position locators, and the like designedfor use within vehicles.

The present invention can be used in a vehicle environment. The dynamicbattery emulator 110 can be disposed between the vehicle and theelectronic device 150 and communicate and/or monitor the actions ofboth. As noted, the power unit 440 can receive power from the vehicle'spower source 450. The electronic device 150 can be removable from thedynamic battery emulator 110, and the dynamic battery emulator 110 canbe securely attached to the vehicle once installed, but this need not bethe case.

For purposes of understanding the present invention, a vehicle typicallyincludes a battery and some sort of ignition or power initiation method.The battery or similar device stores electrical energy and provides thesame to start and run the vehicle's engine, (or power electric motors inthe case of an electric vehicle), and to power any vehicle accessories.In this regard, the term “ignition” means any form of off-to-on switchthat may be used to turn a vehicle off and on, respectively. Thus, eventhough an electrical vehicle may not use an internal combustion engine,it may be turned on and off with its ignition switch.

The dynamic battery emulator 110 of the present invention can beelectrically disposed between the vehicle and the electronic device 150when the electronic device 150 is connected to the dynamic batteryemulator 110. The dynamic battery emulator 110 can provide powermanagement via the controller 414, control/signaling circuitry 416and/or programmable timer 418. The dynamic battery emulator 110 canprovide battery emulated power via the power unit 440, audio signals viathe analog inputs 412, and an electronic device interface via thecontrol/signaling circuitry 416.

The dynamic battery emulator 110 can operate in a plurality of modes.For example, the dynamic battery emulator 110 can operate in off, sleep,and active modes. In the off mode, the dynamic battery emulator 110 isnot dissipating or draining significant power (e.g., less than 3, 2, 1,or 0.5 mA) from the vehicle. In the active mode, the dynamic batteryemulator 110 is drawing power from the vehicle (e.g., at between 10-3000mA) and the internal components of the dynamic battery emulator 110 aretypically fully powered. In the sleep mode, the dynamic battery emulator110 is drawing a limited amount of power from the vehicle (e.g., between1-10 mA), but all of the internal components of the dynamic batteryemulator 110 are either powered down or in a very low power mode.

The control circuit 410 can be a logic circuit that at least partiallycontrols the overall operation of the dynamic battery emulator 110 bycontrolling the power within the dynamic battery emulator 110 and thepower flowing to the electronic device 150 through the dynamic batteryemulator 110. For instance, the control circuit 410 may function topower down the various portions of the dynamic battery emulator 110 atselected times, such as by powering down an audio sub-system when theelectronic device 150 is not actively involved in a call and theignition is turned off.

The control circuit 410 can communicate with the electronic device 150through the interface port, and with various other portions of thedynamic battery emulator 110, such as power unit 440, audio sub-system,etc. The controller 414 of the control circuit 410 can include anoperational sleep mode wherein the very low power is consumed. In thissleep mode, the microprocessor preferably monitors for interrupts, suchas the IGNIT - - - STAT(ON) and PHONE STAT(ON) interrupts describedbelow, generated by other portions of the control circuit 410, andassumes a normal awake mode upon detection of such interrupts.

Conversely, the controller 414 can enter the operational sleep mode whenthe other portions of the dynamic battery emulator 110 and theelectronic device 150 if connected, are powered down. Any known logicfor the control circuit 410 may be used to implement these functions.Further, controller 414 can include or communicate with, suitableregisters for storing and receiving various status flags.

The power unit 440 can operate to convert power from the vehicle to atype suitable for emulating a battery and directly powering theelectronic device 150. The audio sub-system can operate to control aspeaker and microphone associated with the dynamic battery emulator 110so as to generate and detect audible sounds. The phone interface portallows communication between various parts of the dynamic batteryemulator 110 and the electronic device 150, including the exchange ofcommand and status information.

The ignition sensor monitors the ignition sense line for indicationsthat the vehicle's ignition has been turned on or off as describedbelow. The controller 414 can monitor the current status of thevehicle's ignition and track the present and past history of theelectronic device 150 so as to update the relevant status informationfor the controller 414 to perform power management. In addition, theignition sense controller also can communicate with the electronicdevice 150, typically via the interface port, to send power-on andpower-off commands. The ignition sense controller may be any suitablelogic circuit, for example a state machine, and may be a portion of thecontroller 414 or may be a separate module. The ignition sensecontroller can communicate with the controller 414, with the electronicdevice 150 via the interface port, and with the ignition sensor. Theignition sense controller can utilize one or more timers. For example,the ignition sense controller can utilize an install timer, a safetytimer, and an ignition sense timer (IS timer). The install timer and thesafety timer can be designed for long periods of time, on the order ofone or more hours, days, or weeks (e.g., at least 1, 2, 3, 4, 5, 6, 12,or 24 hours; 2, 2, 3, 4, or 6 days; or 1, 2, 3, 4 or more weeks). The IStimer can be designed for shorter periods of time, such as less than 30,20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1minutes. These timers may be of any hardware or software type known inthe art.

The dynamic power adapter 110 can be electrically connected to thevehicle by three lines or using other methods. For example, thefollowing methods could be used: optical, wireless, sensors,transducers, and/or electro-mechanical devices. Two direct power linescan connect the dynamic power adapter 110 to the vehicle's battery viathe vehicle's main electrical system. These lines are typically referredto as positive and ground, and are typically unswitched by thevehicle—meaning that the dynamic battery emulator 110 may form a circuitwith them and pull power from the battery at the discretion of thedynamic battery emulator 110. In addition, the control circuit 410 maybe connected to the vehicle by an ignition sense line. This ignitionsense line is preferably connected to some switched line in the vehiclesuch that the switched line is inactive when the vehicle's ignition isnot on. However, as described below, the present invention alsofunctions to determine when the ignition sense line is either notinstalled or incorrectly installed. Thus, the ignition sense line is notalways connected to a switched line in the vehicle.

The control circuit 410 can control the operation of the dynamic batteryemulator 110. In illustration, the control circuit 410 can have thefollowing states: ISOFF - - - POFF; ISOFF - - - PON; ISON - - - PON;ISON - - - POFF; IS - - - TO; WAIT, and AUTO - - - OFF. At the firstinitialization, the vehicle ignition sense status flag (VISS) is set toa default of NOT - - - INSTALLED, and the call status flag (CALLSTAT) isset to a default of IDLE. The VISS flag is intended to be an indicatorof the status of the installation of the ignition sense line. The VISSflag has three settings, INSTALLED - - - OK for a good installation,INSTALL - - - ERR for an installation error, and NOT - - - INSTALLED foran indication that the ignition sense line is not installed. TheCALLSTAT flag is intended to indicate the status of an active electronicdevice 150 and may be any number of states, such as idle, calling,connecting, active, hold, waiting, alerting, busy, etc. For purposes ofthis invention, these states may be grouped into two classes, IDLE andACTIVE. The IDLE class includes the idle state; the ACTIVE classincludes all other states of the active electronic device 150. Ofcourse, a powered off electronic device 150 will have no active state.

Upon first being installed, the control circuit 410 can enter theISOFF - - - POFF state. In this state, both the electronic device 150and the ignition are off. Upon entering the ISOFF - - - POFF state, thecontrol circuit 410 should be asleep, but monitoring for either theignition or the electronic device 150 being turned on. For instance, thecontrol circuit 410 could monitor the interface port and check fortimeouts. If there are timeouts on the interface port, the controlcircuit 410 may assume that the electronic device 150 is off Otherwise,the electronic device 150 may be assumed to be on. A similar type ofdetection approach may be done with the ignition sense line. Uponreceipt of an indication that either the electronic device 150 has beenturned on (PHONE - - - STAT(ON) interrupt) or the ignition has beenturned on (IGNIT - - - STAT(ON) interrupt), the controller 414 of thecontrol circuit 410 can awaken. When the controller 414 is awake, thepower draw from the vehicle will be higher. For example, it can be above25 milliamps. In the sleep mode, the controller 414 draws very littlecurrent (e.g., less than 2 or 1 milliamps) while it waits for an actionfrom the vehicle, electronic device, control/signaling circuitry, orprogrammable timer that turns to controller 414 into the awake mode.

For the typical embodiment being discussed, the ignition sensingfunctions can be operational when the controller 414 is awake or insleep mode. The control circuit 410 can, in the ISOFF - - - POFF state,check for either an IGNIT - - - STAT(ON) or a PHONE - - - STAT(ON)interrupt. The IGNIT - - - STAT(ON) interrupt is generated by theignition sensor and occurs when a signal is detected on the ignitionsense line. The PHONE - - - STAT(ON) interrupt occurs when acommunications channel is established between the electronic device 150and a remote device.

Upon notice of an IGNIT - - - STAT(ON) interrupt in the ISOFF - - - POFFstate, the ignition sense functionality of the controller 414 can setthe VISS flag to INSTALLED - - - OK to indicate that at least somesignal has been received on the ignition sense line, sets the installtimer to a long period such as twelve hours, and enters the ISON - - -POFF state. For reference, the install timer is intended to assist indetermining whether the ignition sense line is properly installed. Ifthe install timer expires, then this is an indication that the ignitionsense line, while installed, is not installed properly.

Alternatively, upon notice of the PHONE - - - STAT(ON) interrupt in theISOFF - - - POFF state, the VISS flag is checked. If the VISS flag isnot equal to INSTALLED - - - OK, the safety timer can be set to a longperiod, such as twelve hours. If the VISS flag is INSTALLED - - - OK,the safety timer can be set to a shorter period, such as one hour. Forreference, the safety timer can be optionally provided to help insurethat the vehicle battery is not unduly drained. Additionally, the analogcircuitry measures the voltage of the vehicle trigger voltage, if thisvoltage is below a programmable voltage in the controller 414, then adecision can be made to not power the device. Another option would be topower the device and send the information via the device's signalingconnection and wirelessly transmit the low battery condition. Uponexpiration of the safety timer, the dynamic battery emulator 110 canstop drawing more than one milliamp of power from the vehicle. Thedifferent setting times of the safety timer are provided so that theelectronic device 150 is less likely to unexpectedly power down on auser when the ignition sense line is either not installed correctly ornot installed at all, or the voltage is below a specified level, but canpower down after a shorter period of time to conserve vehicle power whenthe ignition sense line is installed correctly. After setting the safetytimer, the ignition sense functionality of the controller 414 can enterthe ISOFF - - - PON state.

In the ISOFF - - - PON state the ignition is off, but the electronicdevice 150 is still on. If, while in this state, the controller 414 canreceive an indication of an active electronic device 150 status, theCALLSTAT flag is updated. If, instead, the safety timer expires, theCALLSTAT flag can be checked. If the status is IDLE, the controller 414can instruct the electronic device 150 to begin powering down (turnoff); if the status is not IDLE, the safety timer can be reinitializedto a suitably distant time, such as one hour. Likewise, if a keypress isnoted, the VISS flag can be checked and the safety timer can bereinitialized to either twelve hours or one hour depending on whetherthe VISS flag is INSTALLED - - - OK or not. At the conclusion of theabove situations, the controller 414 can remain in the ISOFF - - - PONstate. The reinitializing of the safety timer helps prevent untimelyturning off of the electronic device 150, and is done in the ISOFF - - -PON state when there is some indication that the electronic device 150is being actively used.

In contrast, if while in the ISOFF - - - PON state, the PHONE - - -STAT(OFF) interrupt is received, indicating that the electronic device150 has completed a power down, the controller 414 returns to theISOFF - - - POFF state. It is anticipated that the phone power down insuch a situation will be because of user action; specifically, the userwill have manually pressed an on/off switch on the electronic device150, or otherwise directly indicated to the electronic device 150 thatit should turn off, such as by voice command or similar means. This typeof “user action” power off is to be contrasted with the “automatic”powering down of the electronic device 150 under the direction of thedynamic battery emulator 110, as discussed in more detail below. Inaddition, the dynamic battery emulator 110 treats the removal of theelectronic device 150 from the dynamic battery emulator 110 as theequivalent to the sending of a PHONE - - - STAT(OFF) interrupt.

Instead, if while in the ISOFF - - - PON state, an IGNIT - - - STAT(ON)interrupt is received, indicating that the vehicle ignition has beenturned on, the VISS flag is set to INSTALLED - - - OK, the install timeris reinitialized to its' set expiration time, the safety timer isdisabled without expiring, and the controller 414 enters the ISON - - -PON state.

In the ISON - - - POFF state, the ignition is on, but the electronicdevice 150 is off. If, while in this state, the install timer expires,the VISS flag is changed to INSTALLED - - - ERR and the controller 414remains in the ISON - - - POFF state. If the controller 414 receives anPHONE STAT(ON) interrupt, indicating that the electronic device 150 hascompleted a power up, the controller 414 goes to the ISON - - - PONstate. If instead, an IGNIT - - - STAT(OFF) interrupt is received, theVISS flag is set to INSTALLED - - - OK, the install timer is disabledwithout expiring, and the controller 414 enters the ISOFF - - - POFFstate.

In the ISON - - - PON state, both the ignition and electronic device 150are on. If, while in this state, the install timer expires, the VISSflag is changed to INSTALLED - - - ERR and the controller 414 remains inthe ISON - - - PON state. If, instead, the controller 414 receives anindication of a call status change, the CALLSTAT flag is updated and thecontroller 414 remains in the ISON - - - PON state. If the controller414 receives a PHONE - - - STAT(OFF) interrupt, indicating that theelectronic device 150 has completed a power down, the controller 414enters the ISON - - - POFF state. If an IGNIT - - - STAT(OFF) interruptis received, the VISS flag is set to INSTALLED - - - OK, the installtimer is disabled without expiring, the IS timer is set to a very shortperiod of time, such as twenty seconds, and the controller 414 entersthe IS - - - TO state.

In the IS - - - TO state, the ignition is off and the electronic device150 is on. If, while in this state, the controller 414 receives anindication of an active electronic device 150 status, the CALLSTAT flagis updated. Likewise, if a keypress is noted, the IS timer 56 isreinitialized to twenty seconds. At the conclusion of the abovesituations, the controller 414 remains in the IS - - - TO state. If thePHONE - - - STAT(OFF) interrupt is received, indicating that theelectronic device 150 has completed a power down, the IS timer isdisabled without expiring and the controller 414 returns to theISOFF - - - POFF state. If an IGNIT - - - STAT(ON) interrupt isreceived, the IS timer is disabled without expiring, and the controller414 enters the ISON - - - PON state.

If the IS timer expires, the CALLSTAT flag is checked. If the CALLSTATflat is not IDLE, the IS timer is reinitialized to twenty seconds andthe controller 414 remains in the IS - - - TO state. If the CALLSTATflag is IDLE, the controller 414 instructs the electronic device 150 topower down, such as by sending a PHONESTATUS(OFF) request to theelectronic device 150 via the interface port, and the controller 414goes to the WAIT state. The instructing of the electronic device 150 topower down is the start of an “automatic” power down.

In the WAIT state, the ignition is off and the electronic device 150should be in the process of powering down. This state is essentially await state between the IS - - - TO state and the AUTO - - - OFF state.While in this state, if the IGNIT - - - STAT(ON) interrupt is received,the controller 414 goes to the ISON - - - PON state. If call statechange occurs, the updated CALLSTAT is checked; if IDLE, the controller414 remains in the WAIT state, if not IDLE, the IS timer isreinitialized to twenty seconds and the controller 414 reenters theIS - - - TO state. If the PHONE - - - STAT(OFF) interrupt is received,indicating a successful power down of the electronic device 150, thecontroller 414 goes to the AUTO - - - OFF state. In this situation, the“automatic” power down of the electronic device 150 is complete uponreceipt of the PHONE - - - STAT(OFF) interrupt.

In the AUTO - - - OFF state, both the ignition 14 and the electronicdevice 150 are off. This state differs from the ISOFF - - - POFF statein that it can only be entered by the controller 414 causing theelectronic device 150 to turn off after the user turns off the ignition(and the IS timer expires). The primary purpose of this state is toallow the electronic device 150 to be automatically turned on when thevehicle ignition is turned on. If, while in this state, the PHONE - - -STAT(ON) interrupt is received, indicating that the user has intervenedto turn on the electronic device 150, the safety timer is set to onehour and the controller 414 enters the ISOFF - - - PON state. If,instead, the IGNIT - - - STAT(ON) interrupt is received, the controller414 issues an instruction to the electronic device 150 to begin poweringup, such as by sending a PHONESTATUS(ON) request to the electronicdevice 150 via the interface port, and the controller 414 enters theISON - - - POFF state.

In the AUTO - - - OFF mode and the ISOFF - - - POFF states, the controlcircuit 410 should be in the sleep mode, thereby reducing the powerdrain of the dynamic battery emulator 110 to less than one milliamp. Inthe other modes, the control circuit 410 should be in the active mode.

Overall, the safety timer can be used to ensure that the electronicdevice 150 is powered off by at least a specified time after theignition is turned off. The install timer and the VISS flag interact toverify that the ignition sense line is properly installed. The IS timerallows a short waiting period to run after the ignition is turned offbefore instructing the electronic device 150 to begin powering down. Theparticular time periods used for these timers in the description aboveare merely preferred settings and do not represent limitations; instead,a wide variety of timer periods are possible as a matter of designchoice.

The controller 414 represents one approach for updating various statusflags for use by other processes of the dynamic battery emulator 110. Inaddition, the ignition sense controller logic described above performsseveral unique functions. First, the scheme changes the response of thedynamic battery emulator 110 to the ignition being turned on so as todepend not only on the state of the ignition, but also on the history ofthe electronic device 150. That is, the scheme will automatically turnoff an idle electronic device 150 after a short period of time (uponexpiration of the IS timer) once the ignition is turned off. Further,the scheme will automatically instruct the electronic device 150 topower on in response to the ignition being turned on, when the scheme isresponsible for earlier turning off the electronic device 150. However,in contrast to the prior art, the scheme will not instruct theelectronic device 150 to power on when the ignition is turned on in thespecial case of the user having previously intervened to turn off theelectronic device 150. For ease of reference, this feature is called theuser priority feature.

Second, the scheme allows for the propriety of the ignition sense lineinstallation to be checked. If not installed, then the VISS flag willremain at NOT - - - INSTALLED, and the only available states will beISOFF - - - POFF and ISOFF - - - PON. If installed incorrectly, the VISSflag will be set to INSTALLED - - - ERR when the install timer expires.This normally indicates that the ignition sense line is installed to anon-switched line and is therefore incorrectly installed. If theinstalled timer expires, even though the ignition sense line is properlyinstalled (such as when the vehicle is a long-haul truck that operatesfor more than twelve hours continuously), the VISS flag can be rest toINSTALLED - - - OK before entering the ISOFF - - - POFF or IS - - - TOstates. If the ignition sense line is improperly installed, the onlyavailable states are ISOFF - - - POFF, ISOFF - - - PON, ISON - - - POFF,and ISON - - - PON. Once the install timer expires, the only availablestates are ISOFF - - - POFF and ISOFF - - - PON. For ease of reference,this feature is called the installation check feature.

Third, the scheme allows for a safety timer to be intelligently set andreset when it is readily apparent that the user is interacting with theelectronic device 150. For ease of reference, this feature is called theintelligent safety feature.

While the embodiment described above has the user priority feature, theinstallation check feature, and the intelligent safety feature, this isnot required. Instead, any one of these features may be present whilethe others are optional. Thus, some embodiments may have the userpriority feature only, while others may have the user priority featureand the installation check feature but not the intelligent safety; andstill others may have the installation check feature and the intelligentsafety, but not the user priority feature, etc.

Thus, with the present invention, the power management of acommunications accessory may be set not only in regards to the state ofthe vehicle ignition, but also to the history of the electronic device150 attached to the dynamic battery emulator 110. Such a powermanagement scheme allows the electronic device 150 to be automaticallyinstructed to power on by the dynamic battery emulator 110 when thedynamic battery emulator 110 is the cause of the electronic device 150being powered off. If instead, the user powers off the electronic device150, the dynamic battery emulator 110 will not turn on the electronicdevice 150 without user intervention.

Separately or combined therewith, the power management scheme mayoptionally include a method for determining whether the ignition senseline 74 has been correctly installed.

Finally, from the above description, it should be apparent that thesafety timer is used to prevent the electronic device 150 from drainingthe vehicle battery if the electronic device 150 is for some reason lefton in the vehicle for a long time, without having the ignition senseline installed correctly. It should be noted that the safety timer,while preferred, is not required.

FIG. 5 depicts a schematic diagram of a power unit 440 of the dynamicbattery emulator, which is useful for understanding the presentinvention. The power unit 440 can be a typical inductive switching powersupply circuit with feedback, filtering, and indicator. It can becontrollable from an external device or circuitry. This is a costeffective solution, but other circuitry could be used to translate thevehicle's power to a voltage and current suitable to power theelectronic device. The power unit 440 can provide a constant-voltageover a varying load condition and can supply a large amount of currentto the device.

FIG. 6 depicts a schematic diagram of a control circuit 410 of thedynamic battery emulator, which is useful for understanding the presentinvention. In this diagram, the analog inputs 412, controller 414,control/signaling circuitry 416 and programmable timer each can beincluded as components of the controller 600. The controller 600 canmake decisions based on input signal and the state of the electronicdevice.

In one embodiment, the control circuit 410 can include protectioncircuitry and current limiting of the analog trigger signaling from thevehicle. This circuitry allows a large range of analog signaling totrigger the control algorithms in the controller 600.

A dedicated power supply 420 with current limit and over-voltageprotection can be provided for the controller circuitry and algorithms.Again, this allows a large range of voltage input to be applied to thedevice without damaging sensitive circuitry.

FIGS. 7-9 depict various connectors that may be included with thepresent invention. The connectors can connect to various componentsdepicted in the schematic diagrams of FIGS. 5-6, as indicated by thevarious connection points A-F.

The connector 700 of FIG. 7 can be a connector interface into theelectronic device signaling control.

The connector 800 of FIG. 8 can be an in-circuit programming interfaceto load software into the microcontroller version of this invention.This allows for easily modifiable algorithms for different customers,electronic devices, or applications. For example, the timing orsignaling can be changed in software and programmed in through thisinterface at any time.

The connector 900 of FIG. 9 can be used as a jumper to select differentelectronic devices and the appropriate signaling required to turn themON/OFF or any additional tasks. This can be an analog or digital levelto support options for a large number of electronic devices. Forexample, an analog voltage level of a 8-bit ADC could support 256 ormore different voltage levels corresponding to different devices.

FIG. 10 is a flowchart presenting a method 1000 of controlling theon/off state of an electronic device connected to a vehicle, which isuseful for understanding the present invention.

The present invention may, of course, be carried out in other specificways than those herein set forth without departing from the spirit andessential characteristics of the invention. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

The terms “a” and “an,” as used herein, are defined as one or more thanone. The term “plurality,” as used herein, is defined as two or morethan two. The term “another,” as used herein, is defined as at least asecond or more. The terms “including” and/or “having,” as used herein,are defined as comprising (i.e. open language).

Moreover, as used herein, ordinal terms (e.g. first, second, third,fourth, fifth, sixth, seventh, eighth, ninth, tenth, and so on)distinguish one message, signal, item, object, device, system,apparatus, step, process, or the like from another message, signal,item, object, device, system, apparatus, step, process, or the like.Thus, an ordinal term used herein need not indicate a specific positionin an ordinal series. For example, a process identified as a “secondprocess” may occur before a process identified as a “first process.”Further, one or more processes may occur between a first process and asecond process.

This invention can be embodied in other forms without departing from thespirit or essential attributes thereof. Accordingly, reference should bemade to the following claims, rather than to the foregoingspecification, as indicating the scope of the invention.

What is claimed is:
 1. A dynamic battery emulator for replacing thebattery in a portable electronic device when the device is located in oron a vehicle having an electrical system, the dynamic battery emulatorcomprising: a power control module capable of varying its output voltageto adapt to the voltage requirements of an attached portable electronicdevice; an input for conveying electrical power from the vehicle'selectrical system to the power control module; an output for providingelectrical power to the portable electronic device; an output forcommunicating a control signal from the power adaptor to the portableelectronic device to selectively turn on and off the portable electronicdevice; a battery replacement module configured to replace the batteryin a portable electronic device and comprising battery replacementcircuitry for transferring electrical power from the power controlmodule to the portable electronic device via the output for providingelectrical power; an ignition sense controller for determining the powerstate of the vehicle's electrical system; and in communication with theignition sense controller, at least one timer and switch for reducingthe conveyance of electrical power from the vehicle's electrical systemto the portable electronic device at a predetermined time after thevehicle's ignition or electrical system is turned off; wherein, whenconnected to the portable electronic device and the vehicle's electricalsystem, the battery emulator provides electrical power to the portableelectronic device of between 90-110% of the same voltage, impedance,current, and capacitance as the portable electronic device's battery. 2.The dynamic battery emulator of claim 1, wherein the battery replacementmodule conveys power from the power control module to terminals withinthe portable electronic device that are configured to receive electricalpower from the portable electronic device's battery.
 3. The dynamicbattery emulator of claim 1, wherein the ignition sense controllercomprises an analog to digital converter for determining the power stateof the vehicle's electrical system.
 4. The dynamic battery emulator ofclaim 1, wherein the vehicle's electrical power system comprises anignition system and the dynamic battery emulator discrete circuitrywhich limits transmission of voltage spikes from the ignition system. 5.The dynamic battery emulator of claim 1, wherein the portable electronicdevice comprises a location detection system.
 6. The dynamic batteryemulator of claim 1, wherein the timer's predetermined time is set toallow the portable electronic device to complete its pending datatransfer operations before reducing the conveyance of electrical powerfrom the vehicle's electrical system to the portable electronic device.7. The dynamic battery emulator of claim 1, wherein the dynamic batteryemulator comprises and is controllable by a microprocessor which can becontrolled by a stimulus or an algorithm.
 8. The dynamic batteryemulator of claim 1, wherein the dynamic battery emulator draws lessthan 1.0 mA from the vehicle's electrical system.
 9. The dynamic batteryemulator of claim 1, wherein the dynamic battery emulator has less than5% steady-state voltage ripple and corrects transient responses or loadconditions in less than 500 nanoseconds.
 10. A method of controlling theon/off state and a controllable power supply of a portable electronicdevice connected to a vehicle in response to a trigger signal indicatingthat the vehicle has been turned on, wherein the portable electronicdevice turns on when the vehicle's electrical system is powered on, andwherein the portable electronic device comprises a plurality of activecall states including an idle call state and active call state, themethod comprising the steps of: turning on the portable electronicdevice; turning on the vehicle's ignition, and thereafter turning offthe ignition and starting a first timer in response to the turning offof the ignition; automatically instructing the portable electronicdevice to turn off if the first timer expires and the portableelectronic device is in the idle or active call state; thereafter,determining whether the portable electronic device was last turned offin response to the timer expiring; thereafter, turning off thecontrollable power supply connected to the portable electronic deviceafter the signaling to turn off the portable electronic device hasoccurred; thereafter, based on a determination that the portableelectronic device was last turned off in response to the timer expiring,either: automatically turning on the controllable power supply attachedto the portable electronic device in response to the vehicle's ignitionbeing powered on, the automatically turning on including supplying acontrol signal to the portable electronic device instructing theportable electronic device to turn on; or leaving the portableelectronic device turned off state if the vehicle's trigger signal doesnot indicate that the vehicle has been turned on.
 11. A method ofcontrolling the on/off state of a portable electronic device connectedto a vehicle trigger comprising the steps of: monitoring the voltage ofthe vehicle's trigger; automatically turning on a controllable powersupply that emulates a battery attached to the portable electronicdevice, sending signaling to the portable electronic device to turn thedevice “ON”, and continually monitoring the device to make sure it iscontinually “ON”; and upon detection of the vehicle's trigger turningoff, initiating a timer to count down, wherein, upon expiration of thetimer and the vehicle's trigger staying “OFF”, the portable electronicdevice is sent a signal to turn it “OFF” and the controllable powersupply is shut “OFF”; wherein the voltage measured from the vehicle'strigger and the state of the portable electronic device are constantlymonitored.
 12. The method according to claim 11, wherein a controldevice monitors the vehicle's trigger, controls the controllable powersupply, and sends signaling to the portable electronic device to powerit up.
 13. The method according to claim 11, wherein the control devicemonitors the vehicle's trigger and controls an internal timer circuit,whereby, upon completion of a predetermined time delay, signaling issent to the portable electronic device to power the portable electronicdevice “OFF” and to turn “OFF” the controllable power supply.
 14. Themethod of claim 11, wherein the portable electronic device is selectedfrom the group consisting of cellular telephones, personal digitalassistants, and satellite cellular telephones.
 15. The method of claim11, wherein the controllable power supply uses circuitry to protectagainst voltage spikes and excessive power that result from thevehicle's electrical systems, wherein the circuitry comprises amechanism which disables power delivery from the power supply uponsensing a failed condition and reactivates power delivery upon removalof the failed condition.
 16. The method of claim 11, wherein thecontrollable power supply supplies a clean, low-impedance, and regulatedconstant voltage with adequate current to supply dynamic loads tocellular phones, satellite phones, and other accessories.
 17. The methodof claim 11, wherein the controllable power supply utilizes a switchingfrequency and a feedback loop to provide a constant voltage from aninternal reference voltage.
 18. The method of claim 11, furthercomprising the step of electrically connecting the portable electronicdevice to a communications accessory that automatically provides thecontrol signal in response to the vehicle's ignition system poweringoff.